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  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
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  <script>
    //第一种方法 ：typeof x   第二种方法 typeof(x)
    let num = 10
    console.log(typeof num);
    console.log(typeof (num));
  </script>
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